A375523 - OEIS

A375523

a(n) = numerator of Sum_{i=1..n} 1/A171397(i).

1, 3, 11, 25, 137, 49, 363, 761, 7129, 80939, 83249, 1109957, 1135697, 1159721, 2364487, 40916999, 13865893, 267536047, 271415923, 274943083, 6401288429, 6475652719, 32735212187, 33078431987, 300680459483, 43364113769, 1269032646901, 1280123549581, 40016557117411, 3666283538201

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Suggested by A375805.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..2082

EXAMPLE

The first few sums are 1, 3/2, 11/6, 25/12, 137/60, 49/20, 363/140, 761/280, 7129/2520, 80939/27720, 83249/27720, 1109957/360360, 1135697/360360, 1159721/360360, 2364487/720720, ...

MAPLE

b:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(n, base, 10)):

g:= proc(n) option remember; `if`(n<1, 0, g(n-1)+1/b(n)) end:

a:= n-> numer(g(n)):

seq(a(n), n=1..30); # Alois P. Heinz, Aug 30 2024

CROSSREFS

Cf. A171397, A375805, A375524, A001008/A002805.

Sequence in context: A111935 A175441 A001008 * A231606 A096617 A025529

Adjacent sequences: A375520 A375521 A375522 * A375524 A375525 A375526

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Aug 30 2024

STATUS

approved